The invention relates to an electronic sensor array for installation in an automatic gearbox in motor vehicles.
Automatic gearboxes in passenger cars are generally controlled electronically. The control units for automatic gearboxes have hitherto been provided as so-called xe2x80x9cstand-alonexe2x80x9d units in a control box protected against environmental influences, or have been installed directly in the passenger compartment of the vehicle. Recently, practice has changed to integrating the control electronics and the associated sensor system directly into the automatic gearbox. Where automatic gearboxes are concerned, the sensor system is primarily a position detection sensor that is used to sense which driving mode of the automatic gearbox has been set. This is accomplished, for example, by setting the selector switch to one of the positions xe2x80x9cPxe2x80x9d (=Parking), xe2x80x9cRxe2x80x9d (=Reverse), xe2x80x9cNxe2x80x9d (=Neutral) or xe2x80x9cDxe2x80x9d (=Drive). The selector switch is mechanically linked to the automatic gearbox by actuating a selector slide that can move linearly or rotationally. The selector slide is integrated into the hydraulic part of the gearbox controller. The selector slide position is conveyed to the electronic control unit by the position of the selector slide being sensed by the position detection sensor.
In terms of position detection, the prior art teaches an independent sensor packaged in an oil-tight fashion in a housing in order to protect against the surrounding medium, namely gearbox oil. The electrical connection of the sensor via appropriate lines to the control unit must also be oil-tight.
Various measuring principles are conceivable for the actual embodiment of the sensors. For example, it is possible to provide magnetic field sensors that are based on the Hall effect. This is known, for example, from DE 196 03 197 C1. Magnetic field sensors based on the GMR effect (also known as, Giant Magneto-Resistive Effect) are possible. Finally, sensors that operate inductively or capacitively can also be used for sensing the position of a metal part on the selector slide.
In addition to the position detection sensors, rpm sensors, pressure sensors and temperature sensors are also important.
German Published, Non-Prosecuted Patent Application DE 41 42 727 A1 discloses an rpm sensor in which the interior of a pot-shaped lid is closed and sealed with a supplementary lid. In this way, a printed circuit board disposed in the interior is protected, with its electronic circuitry and electronic components, such as a Hall element, for example, against dust, fluids, vapors and the like. Electrical leads make the electrical connection of the sensor to the outside. In order to ensure the operational capability of the sensor, this electrical connection must also be effected in a sealed fashion.
Commonly-assigned German Published, Non-Prosecuted Patent Application DE 38 27 937 A1 discloses how the measuring circuit of an electrical measured value sensor is connected to a connecting cable by a flexible line element, for example a flexible printed circuit board. This configuration also requires, on the one hand, the housing of the measured value sensor to be sealed and, on the other hand, the electrical connection with conductors of the connecting cable to be embodied in a sealed fashion.
A disadvantage of the prior art sensor arrays is the high cost of oil-tight installation and connection of the sensors to the control electronics.
It is accordingly an object of the invention to provide an electronic sensor array that overcomes the hereinafore-mentioned disadvantages of the heretofore-known devices of this general type and that provides a particularly simple and cost-effective way of integrating sensors into an automatic gearbox.
With the foregoing and other objects in view, there is provided, in accordance with the invention, an electronic sensor array for installation in an automatic gearbox. The sensor array includes a housing having a baseplate and a housing lid connected to the baseplate. The housing has a fluid-tight interior and the baseplate has a side facing the housing lid. A flexible conductor track foil mounts on the side of the baseplate facing the housing lid and extends over the interior. A sensor element is disposed in the interior and electrically connects to the flexible conductor track foil. A detector element which may also be referred to as a pick-up element is disposed outside the housing and interacts with the sensor element.
An advantage of the invention of the instant application is that a xe2x80x9cstand-alonexe2x80x9d housing is eliminated. The conductor track carrier is embodied as a flexible conductor track foil connected to the housing lid in a fluid-tight fashion. As a result, the fluid-tight connection of the conductor track foil to the baseplate is not necessary. The interior of the housing separately need not be sealed with a sealing compound.
In accordance with another feature of the invention, the flexible conductor track foil is bonded onto the baseplate. The baseplate can be composed of plastic or a paramagnetic metal, such as aluminum.
In accordance with another feature of the invention, the sensor element can be a position detection sensor.
In accordance with another feature of the invention, the sensor element is a Hall sensor and the detector element is a magnet.
In accordance with another feature of the invention, the baseplate has an outside and the detector element is disposed on the outside of the baseplate.
In accordance with another feature of the invention, the sensor element is an rpm sensor. A rotatable detect wheel having a circumference can be included. The detector element is disposed on the circumference of the rotatable detector wheel.
In accordance with another feature of the invention, the sensor element is located on a side of the baseplate. The detector element is disposed on the same side of the baseplate as the sensor element.
In accordance with another feature of the invention, the electronic sensor includes a mounting element connected to the baseplate. The mounting element holds the sensor element.
In accordance with another feature of the invention, the electronic sensor includes a magnet disposed between the sensor element and the baseplate. The magnet interacts with the sensor element.
In accordance with another feature of the invention, Hall sensors have proven advantageous as position detection sensors. The electrical connection to the control electronics then preferably employs bonding.
Other features that are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in an electronic sensor array, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.